Hand function, not proximity, biases visuotactile integration later in object processing: An ERP study

Does hand position affect orienting when no action is required? An electrophysiological study

“…Average waveforms were calculated for each participant and condition. Previous studies (Simon-Dack et al, 2009;Reed et al, 2013;Vyas et al, 2019) and visual analysis of the grand average waveforms were used to select the left hemisphere (LH) and right hemisphere (RH) electrode clusters that correspond with parieto-occipita bimodal neuron regions (Simon-Dack et al, 2009). Electrodes 140,141,151,152,160,and 161 formed the RH cluster;97,98,99,107,108, and 109 formed the LH cluster (Figure 1D).…”

“…Hand position can affect visual processing in at least two ways, via multisensory integration early in processing potentially through bimodal neurons (Graziano and Gross, 1998) or through more topdown allocations of attentional resources across the visual field (Mangun et al, 1993). Previous research has shown that attention can be biased to targets appearing near the hand that require action responses and has argued that attention to locations near the hand facilitates upcoming action (Reed et al, 2013(Reed et al, , 2018Vyas et al, 2019). It is unclear whether attention orients to non-targets near the hand not requiring responses.…”

“…It is unclear whether attention orients to non-targets near the hand not requiring responses. Using electroencephalography/eventrelated potentials (EEG/ERP), this study investigated whether hand position affected visual orienting to non-targets under conditions that manipulated the distribution of attention (Simon-Dack et al, 2009;Qian et al, 2012;Reed et al, 2013Reed et al, , 2018Vyas et al, 2019).…”

“…Stimuli near the hand elicit attentional shifting (Lloyd et al, 2010), attentional prioritization of space (Abrams et al, 2008), and more accurate detection and discrimination of visual stimuli (Dufour and Touzalin, 2008). Action-relevant properties of the hand or tools appear to be important for the hand proximity effect (e.g., Reed et al, 2010;Thomas, 2015;Vyas et al, 2019). Finally, the hand proximity effect is also affected by attentional set, as manipulated by task instructions (Garza et al, 2013).…”

“…The P3, a positive inflection occurring between 300-500 ms in parietal electrodes, is associated with event categorization and higher-order cognitive influences such as task relevance, attentional distributions and motivation (Kok, 2001). Hand location near a visually presented stimulus increases the amplitude of early contralateral components (P1, N1; Reed et al, 2013) without discriminating between target (i.e., stimuli that require action) and non-target (i.e., stimuli that do not require action) stimuli and also increases the amplitude of P3 amplitudes for targets relative to non-target stimuli (Reed et al, 2013(Reed et al, , 2018Vyas et al, 2019).…”